US 7043399 B2 Abstract (Subject)
To provide an electro-magnetic field analysis technique of an electric rotating machine that filters through a specific higher-harmonic at a specific portion.
(Construction)
The first electro-magnetic field analysis procedure of analyzing the electro-magnetic field in an analysis space based on the first boundary condition in terms of an electro-magnetic variable assigned to the first specific portion in the analysis space; a development procedure
2 of developing the electro-magnetic variable at the second specific portion in the analytic space, obtained in the first electro-magnetic field analysis procedure, into each higher-harmonic component; the second boundary condition setting procedure of assigning an electro-magnetic variable in terms of at least one of the higher-harmonic components, developed from the above electro-magnetic variable, to the second specific portion as the second boundary condition; and a procedure 3 of analyzing the electro-magnetic field of the analysis space based on the first and second boundary conditions are executed on a computer.Claims(13) 1. An electro-magnetic field analysis program of an electric rotating machine for a computer to execute:
the first electro-magnetic field analysis procedure of analyzing the electro-magnetic field in an analysis space based on the first boundary condition in terms of an electro-magnetic variable assigned to the first specific portion in the analysis space;
a development procedure of developing the electro-magnetic variable at the second specific portion in the analytic space, obtained in the first electro-magnetic field analysis procedure, into each higher-harmonic component;
the second boundary condition setting procedure of assigning an electro-magnetic variable in terms of at least one of the higher-harmonic components, developed from the above electro-magnetic variable, to the second specific portion as the second boundary condition; and
a procedure of analyzing the electro-magnetic field of the analysis space based on the first and second boundary conditions.
2. An electro-magnetic field analysis program of an electric rotating machine according to
3. An electro-magnetic field analysis program of an electric rotating machine according to
4. An electro-magnetic field analysis program of an electric rotating machine according to
5. An electro-magnetic field analysis program of an electric rotating machine according to
6. An electro-magnetic field analysis program of an electric rotating machine according to
7. An electro-magnetic field analysis program of an electric rotating machine for a computer to execute:
a total electro-magnetic field analysis procedure of analyzing the total electro-magnetic field of the electric rotating machine by assigning a boundary condition to the outer boundary surface of the analysis space and applying a magneto-motive force by current or magnetic force;
a procedure of storing the permeability distribution in the magnetic substance obtained in the total electro-magnetic field analysis procedure;
a procedure of developing the potential, which describes the electro-magnetic field distribution on the sliding surface between the rotor and stator obtained in the total electro-magnetic field analysis, into multiple higher-harmonic components that have some distribution in the axial direction and a constant or periodic distribution in the direction of rotation;
a procedure of accomplishing a linear electro-magnetic field analysis in each rotor space including the rotor and stator space including the stator, wherein the same boundary condition as in the total electro-magnetic field analysis procedure is assigned, a Dirichlet's condition is assigned to the sliding surface, the stored permeability distribution is assigned and fixed to the whole analysis space, and current or magnetic force applied in the total electro-magnetic field analysis procedure is applied; and
a procedure of accomplishing a linear electro-magnetic field analysis in each rotor space including the rotor and stator space including the stator, wherein the same boundary condition as in the total electro-magnetic field analysis procedure is assigned, the higher-harmonic components are assigned, one after another, to the sliding surface as the boundary condition, the permeability distribution is assigned to the whole magnetic substance, and current or magnetic force is set zero.
8. An electro-magnetic field analysis program of an electric rotating machine according to
9. An electro-magnetic field analysis program of an electric rotating machine according to
10. An electro-magnetic field analysis program of an electric rotating machine for a computer to execute:
a total electro-magnetic field analysis procedure of analyzing the total electro-magnetic field of the electric rotating machine in a series of time steps by assigning a boundary condition to the outer boundary surface of the analysis space and applying a magneto-motive force by current or magnetic force;
a procedure of storing the permeability distribution in the magnetic substance in a series of time steps obtained in the total electro-magnetic field analysis procedure;
a procedure of developing and storing the potential, which describes the electro-magnetic field distribution on the sliding surface between the rotor and stator obtained in the total electro-magnetic field analysis, into multiple higher-harmonic components that have some distribution in the axial direction and a constant or periodic distribution in the direction of rotation;
a procedure of abstracting the time and spatial higher-harmonic components by developing the multiple higher-harmonic components which, obtained in the above analysis in a series of time steps, have a constant or periodic distribution in the direction of rotation into higher-harmonic components along the time axis;
a procedure of accomplishing a linear electro-magnetic field analysis in each rotor space including the rotor and stator space including the stator, wherein the same boundary condition as in the total electro-magnetic field analysis procedure is assigned, a Dirichlet's condition is assigned to the sliding surface, current or magnetic force applied in the total electro-magnetic field analysis procedure is applied, and the permeability distribution in the magnetic substance in a series of time steps is assigned in each time step; and
a procedure of accomplishing a linear electro-magnetic field analysis in each rotor space including the rotor and stator space including the stator, wherein the same boundary condition as in the total electro-magnetic field analysis procedure is assigned, the time and spatial higher-harmonic components are assigned, one after another, to the sliding surface as the boundary condition, the permeability distribution in the magnetic substance in a series of time steps is assigned and fixed in each time step, and current or magnetic force is set zero.
11. An electro-magnetic field analysis program of an electric rotating machine according to
12. An electro-magnetic field analysis program of an electric rotating machine according to
13. An electro-magnetic field analysis program of an electric rotating machine according to
Description 1. (Field of the Invention) The present invention relates to the electro-magnetic field analysis technique of an electric rotating machine, particularly to the electro-magnetic field analysis technique of an electric rotating machine that can decompose the electro-magnetic field of the electric rotating machine into multiple higher-harmonic components and leakage magnetic flux that comprise the electro-magnetic field distribution. 2. (Prior Art) A conventional electro-magnetic field analysis of an electric rotating machine employs a time-stepping technique in which the analysis is accomplished step by step as the rotor is turned gradually (for example, see the Non-Patent Document 1). [Non-Patent Document 1] T. W. Preston, A. B. J. Reece and P. S. Sangha: “Induction motor analysis by time-stepping techniques”, IEEE Trans. on Magnetics, vol. 26, No. 2, pp. 551–554, 1990. (Problems to be Solved by the Invention) Vibration, noise, iron loss, eddy current loss, etc. are caused by specific higher-harmonic component. With the conventional electro-magnetic field analysis technique of an electric rotating machine, however, the electro-magnetic field distribution obtained through the analysis contains multiple higher-harmonic components and independent electro-magnetic field analysis of higher-harmonic component is not feasible. In other words, because multiple components are all superimposed in the electro-magnetic field distribution obtained through the conventional electro-magnetic field analysis, there arises a problem that electro-magnetic field distribution by each specific higher-harmonic, which is useful for identifying a troublesome higher-harmonic or examining a measures to reduce the vibration, noise, iron loss or eddy current loss, is not available. Besides, it would be very much convenient if three-dimensional electro-magnetic field analysis is available in addition to two-dimensional analysis. An object of the present invention is to provide an electro-magnetic field analysis technique of an electric rotating machine, with which the electro-magnetic field distribution of specific spatial higher-harmonic or time higher-harmonic is displayed so that the designer of the rotating machine can obtain information useful for analyzing the vibration and noise. (Means for Solving the Problems) According to an aspect of the present invention, there is provided an electro-magnetic field analysis program of an electric rotating machine for a computer to execute the first electro-magnetic field analysis procedure of analyzing the electro-magnetic field in an analysis space based on the first boundary condition in terms of an electro-magnetic variable assigned to the first specific portion in the analysis space; a development procedure of developing the electro-magnetic variable at the second specific portion in the analytic space, obtained in the first electro-magnetic field analysis procedure, into each higher-harmonic component; the second boundary condition setting procedure of assigning an electro-magnetic variable in terms of at least one of the higher-harmonic components, developed from the electro-magnetic variable, to the second specific portion as the second boundary condition; and a procedure of analyzing the electro-magnetic field of the analysis space based on the first and second boundary conditions. There is also provided an electro-magnetic field analysis program of an electric rotating machine for a computer to execute a total electro-magnetic field analysis procedure of analyzing the total electro-magnetic field of the electric rotating machine by assigning a boundary condition to the outer boundary surface of the analysis space and applying a magneto-motive force by current or magnetic force; a procedure of storing the permeability distribution in the magnetic substance obtained in the total electro-magnetic field analysis procedure; a procedure of developing the potential, which describes the electro-magnetic field distribution on the sliding surface between the rotor and stator obtained in the total electro-magnetic field analysis, into multiple higher-harmonic components that have some distribution in the axial direction and a constant or periodic distribution in the direction of rotation; a procedure of accomplishing a linear electro-magnetic field analysis in each rotor space including the rotor and stator space including the stator, wherein the same boundary condition as in the total electro-magnetic field analysis procedure is assigned, a Dirichlet's condition is assigned to the sliding surface, the stored permeability distribution is assigned and fixed to the whole analysis space, and current or magnetic force applied in the total electro-magnetic field analysis procedure is applied; and a procedure of accomplishing a linear electro-magnetic field analysis in each rotor space including the rotor and stator space including the stator, wherein the same boundary condition as in the total electro-magnetic field analysis procedure is assigned, the higher-harmonic components are assigned, one after another, to the sliding surface as the boundary condition, the permeability distribution is assigned to the whole magnetic substance, and current or magnetic force is set zero. A three-dimensional analysis becomes available if the analysis includes a procedure of developing the potential, which describes the electro-magnetic field distribution on the sliding surface between the rotor and stator obtained in the total electro-magnetic field analysis, into higher-harmonic components that have some distribution in the axial direction and a constant or periodic distribution in the direction of rotation. It is preferable that, in the case of analyzing a three-dimensional rotating structure, in the procedure of analyzing the electro-magnetic field of the electric rotating machine by assigning a boundary condition to the outer boundary surface of the analysis space and applying a magneto-motive force by current or magnetic force, a procedure of converting a potential obtained under a gage-free or partially gage-free condition into a potential meeting the gage condition is executed before the procedure of developing the potential into multiple higher-harmonic components that have some distribution in the axial direction and a constant or periodic distribution in the direction of rotation. [ Diagram showing a flowchart of the electro-magnetic field analysis technique of an electric rotating machine according to the first embodiment of the present invention [ Diagram showing a flowchart of the electro-magnetic field analysis technique of an electric rotating machine according to the second embodiment of the present invention [ A supplemental explanatory figure of the electro-magnetic field analysis technique according to the embodiment of the present invention [ Diagram showing a flowchart of the electro-magnetic field analysis technique of an electric rotating machine according to the third embodiment of the present invention [ Diagram showing a flowchart of the electro-magnetic field analysis technique of an electric rotating machine according to the fourth embodiment of the present invention [ Diagram showing a flowchart of the electro-magnetic field analysis technique of an electric rotating machine according to the fifth embodiment of the present invention [ Diagram showing a flowchart of the electro-magnetic field analysis technique of an electric rotating machine according to the sixth embodiment of the present invention [ Diagram showing a flowchart of the electro-magnetic field analysis technique of an electric rotating machine according to the seventh embodiment of the present invention [ Diagram showing a flowchart of the electro-magnetic field analysis technique of an electric rotating machine according to the eighth embodiment of the present invention [ Figure showing a device on which the electro-magnetic field analysis of an electric rotating machine of the present invention is accomplished In this specification, higher-harmonic includes constant component and fundamental as well. The electro-magnetic field analysis technique of an electric rotating machine according to the present invention is described hereunder, using figures. To start with, the electro-magnetic field analysis technique according to the first embodiment of the present invention is described hereunder, using A component electro-magnetic field analysis In the component electro-magnetic field analysis The procedure of the total electro-magnetic field analysis [Formula 1]
If the total analysis space In the spatial higher-harmonic and time higher-harmonic analysis
When the arc bb′, on which the higher-harmonic component of the potential a is developed, is moved on an assumption that the inside peripheral analysis space Next, an electro-magnetic field analysis [Formula 3]
The same current or magnetic force as applied in the total electro-magnetic field analysis In parallel with the electro-magnetic field analysis [Formula 4]
The current or magnetic force as applied in the total electro-magnetic field analysis In the specific spatial higher-harmonic and time higher-harmonic electro-magnetic field analysis Besides, the electro-magnetic field analysis
The electro-magnetic field analysis In the specific spatial higher-harmonic electro-magnetic field analysis [Formula 6]
The current or magnetic force as applied in the total electro-magnetic field analysis
The electro-magnetic field analysis In the specific time higher-harmonic electro-magnetic field analysis [Formula 8]
The current or magnetic force as applied in the total electro-magnetic field analysis According to this embodiment, where the electro-magnetic field distribution of specific spatial higher-harmonic is displayed to the designer of an electric rotating machine, the designer can obtain information useful for analyzing the causes of generated vibration or noise. Next, a three-dimensional analysis technique for expanding the electro-magnetic field analysis into three-dimension is described hereunder. A component electro-magnetic field analysis In the source component electro-magnetic field analysis In the description below, for the sake of easier understanding, a Dirichlet's condition of a=0, under which the electro-magnetic field lies in parallel with the boundary surface, is specified as the boundary condition of the boundary, except for the periodic boundary, on the outside peripheral surface in the total analysis space. The normal Dirichlet's condition of an outside peripheral surface, where the electro-magnetic field intensity is low, is frequently set to a=0 as above. The outside peripheral analysis space Non-linear analysis based on the electro-magnetic characteristic data is employed, wherein current or magnetic force is inputted as the electro-magnetic field source and an analysis by the time-stepping technique is accomplished, one after another, while turning the rotor on the sliding surface bb′. If the total analysis space
The development into components may be accomplished either on a static coordinate system or on a rotary coordinate system on the rotor. Next, an electro-magnetic field analysis In this electro-magnetic field analysis [Formula 10]
If the outside peripheral analysis space In the specific spatial higher-harmonic and time higher-harmonic electro-magnetic field analysis Although the analysis using the magnetic vector potential A has been described herein, the Coulomb gage given by Formula (11) automatically holds true for an analysis of two-dimensional space. [Formula 11]
For an analysis of three-dimensional space, however, it is generally preferable not to fix the gage (divA) but to compute under a gage-free or partially gage-free condition for higher-speed analysis. When the magnetic vector potential A is analyzed, one after another, in time steps, divA fluctuates in each time step because of the above reason, which in turn causes a problem in the case where a physical variable related to the magnetic vector potential A is developed into time higher-harmonic components. To avoid this, it is preferable that the obtained magnetic vector potential A is converted into the magnetic vector potential A′ processed through the Coulomb gage, using Formula (12), in each time step. [Formula 12]
The scalar potential Ψ for the above can be obtained from Formula (13). [Formula 13]
If a new variable a′ given by Formula (14) is used, instead of the variable a, for the scalar potential Ψ obtained as above on each nodal point, the problem due to the fluctuation of the gage is eliminated. [Formula 14]
Ψ
The electro-magnetic field analysis [Formula 16]
The current or magnetic force as applied in the total electro-magnetic field analysis
The electro-magnetic field analysis The current or magnetic force as applied in the total electro-magnetic field analysis In any of the embodiment described above, as shown in The analytical technique described above can naturally be applied to a linear motor of which rotating radius is practically infinite. When applied, the analysis can be accomplished, for example, in the following procedures. They are 1) a total electro-magnetic field analysis procedure of analyzing the total electro-magnetic field of a linear motor by assigning a boundary condition to the outer boundary surface of the analysis space and applying a magneto-motive force by current or magnetic force; 2) a procedure of storing the permeability distribution in the magnetic substance obtained in the total electro-magnetic field analysis procedure; 3) a procedure of developing the potential, which describes the electro-magnetic field distribution on the sliding surface between the needle and stator obtained in the total electro-magnetic field analysis, into multiple localized higher-harmonic components that have some distribution in the direction perpendicular to the moving direction and a constant or periodic distribution in the moving direction; 4) a procedure of accomplishing a linear electro-magnetic field analysis in each needle space including the needle and stator space including the stator, wherein the same boundary condition as in the total electro-magnetic field analysis is assigned, a Dirichlet's condition is assigned to the sliding surface, the permeability distribution is assigned to the whole analysis space, and current or magnetic force applied in the total electro-magnetic field analysis is applied; and 5) a procedure of accomplishing a linear electro-magnetic field analysis in each needle space including the needle and stator space including the stator, wherein the same boundary condition as in the total electro-magnetic field analysis is assigned, the analyzed higher-harmonic components are assigned, one after another, to the sliding surface as the boundary condition, the permeability distribution is assigned and fixed to the whole magnetic substance, and current or magnetic force is set zero. In addition to the above, it is also allowable to accomplish a procedure of displaying the electro-magnetic field distribution, which is obtained through a series of individual analyses of the needle space and stator space, separately by individual boundary conditions. Descriptions in this specification are based on the embodiments but the present invention is not limited to those but can naturally be in various aspects and modes. For example, it is needless to say that the analytical method to be accomplished in accordance with the procedures in the above-mentioned analysis program or an analyzing device thereof is also included in the scope of the present invention. (Effects of the Invention) With the electro-magnetic field analysis technique of an electric rotating machine according to the present invention as described above, various problems caused by specific higher-harmonic component, including vibration, noise, iron loss, and eddy current loss, can be resolved quickly. That is, because the electro-magnetic field distribution of a specific higher-harmonic component or that of leakage magnetic flux alone can be obtained, contributing component in vibration, noise, iron loss or eddy current loss can be identified and a measures for reducing specific higher-harmonic electro-magnetic field from the magnetic flux rays can be determined easily. Thus, the invention produces an effect that the problems resulting from higher-harmonic component, including vibration, noise, iron loss, and eddy current loss, can be reviewed quickly and examination of possible measures for reducing them can be accelerated. Besides, because the technique is applicable not only to two-dimensional analysis but also to three-dimensional analysis, much more precise analysis becomes available. Patent Citations
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